Not long ago, ignorance of any church doctrine and the subsequent belief system was probably an understandable excuse for staying a believer. However, any claims that religions make now takes just minutes to verify with an internet search, whereas it used to take months or years.
Not only that, websites like this allow us all to have a back and forth discussion in real time without waiting for delays in correspondence. Members can cite useful references - all of this saves time. There is no more hiding - extraordinary claims require extraordinary evidence.
There are good reasons that JW's dont like to debate, they are too scared to research any of their deeply held beliefs and this leaves them at a disadvantage. They are forced to lie to themselves and each other in order to maintain loyalty.
Just after 1995, I was at a public talk on a Sunday morning in my early 20's and I was already skeptical. A brother gave a talk about the 7 times (yawn), and used both solar years and lunar years interchangeably to arrive at 1914. I realised then they were making it all up.